Definition of: invasion

(in·vā′zhən) noun
1. The act of invading; a military inroad or incursion for conquest, reconquest, or plunder.
2. Hence, any attack with harmful intent or result: an invasion of disease.
3. Encroachment, as by an act of intrusion or trespass: the invasion of privacy. [<LL invasio, -onis <invasum, pp. of invadere. See INVADE.] Synonyms: aggression, encroachment, foray, incursion, inroad, irruption, raid. See AGGRESSION, ATTACK.